Scale



June 1936- E. J. vo PVEIN ET AL ,045,974

SCALE Filed Nov. 29, 1935 ORNEY UNITED STATES PATENT OFFICE SCALE EdwardJ. Von Pein, Endicott, and William N.

Gilbert, Binghamton, N. Y., assignors to International Business MachinesCorporation, New York, N. Y., a corporation of New York ApplicationNovember 29, 1935, Serial No. 51,996

'7 Claims.

This case relates to the counterbalancing and indicating mechanisms ofWeighing scales.

The invention contemplates novel means for operating an indicator from afloating type of pendulum counterbalance.

The invention also contemplates novel for constraining anindicator-operating element to vertical, rectilinear movement.

means Other objects will appear from the following parts of thespecification and from the drawing which shows the counterbalancing andindicating means in elevation.

Frame l carries spaced, vertical guide bars ll forming tracks forrollers l2, which are suspended by tapes |3 from the guide bars.

Rollers l2 carry pendulums 14, located in parallel, spaced,

planes to permit them to pass each other during a weighing operation, asindicated in dotted lines in the drawing.

Rigidly fastened to each pendulum roller I2 is a cam power sector l5,from which a ribbon l6 extends downwardly to be connected through a tiebuckle H, to one end of an equalizer bar la. The two ribbons [6 are thusconnected to the opposite ends of equalizer bar I8.

Connected to the center of bar I8 is a draft rod l9 which transmits theload force to the equalizer.

Between pendulums I4 is located a sectorshaped member 20, around thearcuate periphery of which the intermediate portion of a tape 2| iswound. The tape extends upwardly from opposite sides of member 20 to befastened at opposite ends to the two pendulum rollers [2.

The tape is fastened intermediately to the central point of the arcuateperipheral portion of member 20.

Member 20 carries, at its center of curvature, a pivot pin 22 whichfreely pivotally mounts a bell crank lever 23, the Vertical arm of whichforms the foot of a rack 24 and the horizontal arm of which is providedwith a weight 25 to maintain the rack in mesh with a pinion 26. Pinion26 is fixed to shaft 27 which carries load indicating pointer 28.

ing to the right.

When a load is applied to the scale, the force of the load istransmitted to draft rod [9 depresses equalizer bar l8.

which Through ribbons IE,

bar I8 when depressed rocks the opposite pendulums l4 upwardly andtowards each other.

As the pendulums rock upwardly, their rollers 12 ride up on the tracksurfaces of bars ll, thus also causing the pendulums to be bodily movedupwardly. When rollers l2 ride up on bars II,

through tape 2|, they raise member 20, rack carrier 22 (including weight25), rack 24, vertical link 30, and check levers 3| and 32. The weightof the parts thus raised by action of rollers [2 functions as additionalload counterbalancemeans supplementing the counterbalance func-' tion ofpendulums l4. As rack 24 rises it rotates pinion 26, its shaft 21, andload pointer 28. The pendulums and the other counterbalance means aremoved until they counteract the load. When these parts come toequilibrium position, pointer 28 indicates the load.

Bar l8 factors the load force into two halves, one half transmitted tothe left hand pendulum and the other half transmitted to the right handpendulum. Each pendulum in turn supports half the weight of member 20and the parts connected to the member. In order for this to be truethroughout operation of, the scale, member 20 must remain during itsrise, along a definite path mid-way between the pendulums, or in otherwords, the center of curvature of member 20 must be maintained along aline half-way between the pendulum rollers [2. Another reason for thisis that if the member 20 moved nearer to one pendulum roller, or out ofits predetermined central 30 path, then rack 24 would be inclined. As aresult, rise of the rack would not rotate pinion 26 (and consequentlyload pointer 28) through the same increments as when the rack is movingparallel to said center line between the pendulum rollers. The scale iscalibrated to indicate the load according to increments of movement ofthe rack when the rack is moving parallel to aforesaid center line andif the rack is in an inclined position with respect to this center line,the increments of movement of the rack will not provide the calibratedindications of load but will indicate less load than is actually on thescale.

Further, when the scale is out of level, all the parts thereof shouldtilt to corresponding extents. It is well known that the oppositependulums will take positions corresponding to the tilt of the scale,one pendulum moving further than normal and the other less than normal.0

Member 20 acts as an equalizer between the 5 pendulums. Thus, when onependulum drops below its normal position for a given load and the otherrises above such normal position, the member 20 will average up thesemovements and its center of curvature will remain at normal 55 heightfor the given load. This again is only true if the center of curvatureof member 20 remains along the center line between the two pendulums.When the scale tilts, this center line also tilts to the same extent,and therefore member 20 must not be permitted to hang vertically whenthe scale tilts but must be constrained to depart from the true verticalin accordance with the tilt.

When the scale tilts, the rack will also tilt but since all the otherparts of the scale including the pendulums are similarly tilted, therelation and interaction between the parts will remain the same as whenthe scale is level, and the calibrated load indications will befurnished by movement of the pointer.

For these several reasons, then, namely; to divide the weight of themember 20, and parts connected therewith, equally between the twopendulums; to maintain the rack 24 movable parallel to. the center linebetween the pendulums; and to permit the member 2a to equalize andaverage the movements of the two pendulums, the center of curvature ofthe member must be maintained along the center line between thependulums. This is done by the check levers 3| and 32 acting throughlink 30.

These check levers are not parallel (as is usual with platform checklinkages) but are non-parallel, extending in diverging directions. Thecheck levers are of equal lengths, and their initial angles to thehorizontal are the same. Thus, the check levers will move through equalangles for any given movement of the member 2!). Accordingly, thefreeend of each check lever will cover an arc equal in length to the arethrough which the other check lever moves at its free end. Since thecheck levers extend in opposite directions from their pivots, theirrespective arcs of movement are opposite in curvature. Further, sincethe check levers diverge and are at the same side of the horizontal, thearcs of movement of the check levers are not only opposite in curvaturebut in a strict directional sense extend oppositely, whereas if thecheck levers were parallel throughout their movement, their arcs, thoughopposite in curvature, would in a directional sense extend in the samedirection.

For the above reasons, the free ends of the check levers, throughout therange of the scale, will be at opposite sides of the center line betweenthe pendulums except at the zero load point (indicated in full lines inthe drawing) and at the maximum load point (indicated in phantom linesin the drawing) when the free ends of the check levers will be directlyon aforesaid center line. Between the zero and maximum load points, thefree ends of the check levers and therefore the upper and lower ends ofconnecting link 30 will be at opposite sides of the center line and-atequal distances from said center line. Therefore, the center point oflink 30 will always remainon said center line.

Since member 2!) is connected by pivot pin 22 to the center point oflink 30 and since pin 22 is at the center of curvatureof member 20, itis evident that by reason of the check lever arrangement and action, thecenter of curvature of member 20 will move along the center line betweenthe pendulums, throughout the range of the scale, which was thedesideratum to. be obtained for the reasons given before.

The operation of the load counterbalancing and indicating means isbelieved clear from the above description of the parts.

It is to be understood that variations, changes,

and modifications may be made which follow the principles of theinvention without departing from the spirit or teachings of theinvention. It is therefore intended to be limited only by the followingclaims. 5

What is claimed is as follows:

1. In a scale; a pair of oppositely rockable load counterbalancingpendulums, an equalizer member, an indicator, a driving element for theindicator carried by the equalizer member, and means for convertingrocking of the pendulums into movement of the equalizer member in avertical direction, said means including a tape suspending the equalizermember equally from the opposite pendulums and a check linkage connected15 to the equalizer member to constrain the latter to movement in saidvertical direction along a definite, predetermined path.

2. In a scale; a pair of oppositely rockable load counterbalancingpendulums including round ful- 20 crum elements, an equalizer memberhaving a round peripheral portion and having the center of curvature ofsaid round portion on: a line passing centrally between the fulcrumelements, tape means wound at opposite ends on the fulcrum 25 elementsand wound intermediately around said round portion of the equalizermember to suspend the latter from the opposite fulcrum elements and tocause vertical movement of said member upon rocking of the pendulums andtheir 30 fulcrum elements, load indicating means operated by the memberupon vertical movement of the member, and a check linkage connected tothe center of curvature of said equalizer member to maintain said centerof curvature along said central line between the fulcrum elements duringvertical movement of the equalizer member.

3. In a scale; a pair of oppositely rockable load counterbalancingpendulums including round fulcrum elements, spaced tracks along whichsaid fulcrum elements roll during rocking of the pendulums, an equalizermember between the fulcrum elements, tape means suspending the equalizermember from the fulcrum elements to cause movement of the equalizermember in a vertical direction upon rocking of the pendulums, anindicator, a shaft therefor, a pinion on the shaft, a rack for drivingthe pinion, means for pivotally mounting the rack on the equalizermember, means for maintaining the rack meshed with the pinion, and acheck linkage connected to the equalizer member at the pivotal axis ofthe rack to constrain the rack and member to movement parallel tothemselves in said vertical direction.

4. In a scale; a pair of oppositely rockable load counterbalancingpendulums, a load indicator, a rectilinearly movable device foroperating the load indicator, connections between the pendulums anddevice for converting rocking of the pendulums into movement of saiddevice in a rectilinear direction, and a check linkage for constrainingthe device to movement parallel to itself in said rectilinear direction,said check linkage including a, link connected at its center toaforesaid device and a pair of non-parallel check levers extending inopposite directions from said link and connected to the link at oppositesides of the link center and at equal distances from the link center.

5. In a scale, a pair of oppositely rockable load counterbalancingpendulums, a load indicator, an equalizer member, means carried by theequalizer member for operating the load indicator, tape means suspendingthe member from 7 the pendulums and causing the member to move in avertical direction upon rocking of the pendulums, a vertically extendinglink connected at the center to said equalizer member, and a pair ofcheck levers connected to the link at equal distances above and belowthe link center, said check lev'ers extending in opposite directionsfrom the link and being arranged at equal angles to the horizontal andat the same side of the horizontal, whereby the link center isconstrained to move along the same vertical line throughout rectilinearmovement of said equalizer member and whereby said equalizer during itsrectilinear movement is held in a definite, predetermined vertical path.

6. In a scale; a pair of oppositely rockable load responsive rollingelements, tracks along which said elements roll, a rounded equalizermember having its center of curvature on a line passing centrallybetween the rolling elements, tape means suspending the equalizer memberfrom the rolling elements to cause vertical movement of the member uponrocking of the elements, a load indicator, means carried by the saidmember for operating the indicator upon vertical movement of the member,a link connected at its center to the center of curvature of saidmember, and a pair of non-parallel check levers extending in oppositedirections from the link and connected thereto at equal distances fromthe link center, the check levers being at similar sides of thehorizontal and at equal distances from the horizontal, whereby the linkcenter and the center of curvature of the equalizer member aremaintained on said center line between the rolling elements throughoutthe range of movement of the rolling elements.

'7. In a scale; a pair of oppositely rockable load responsive spools, anequalizer member symmetrically arranged with respect to a vertical linepassing centrally between the spools, tape means suspending the memberfrom said spools and causing vertical movement of the equalizer memberupon rocking of said spools, a load indicator, means carried by saidmember for operating the indicator upon vertical movement of the member,a vertically disposed link connected at its center to said equalizermember, and a pair of check levers connected to the link above and belowthe link center and at equal distances from the link center, the checklevers extending in opposite directions from the link and arranged atequal angular distances from the horizontal and at the same side of thehorizontal, whereby said link center will be maintained throughoutmovement of the equalizer member along the same vertical line andwhereby the equalizer will be constrained to move parallel to itselfduring its vertical movement.

EDWARD J. VON PEIN. WILLIAM N. GILBERT.

